Chris@10: /*
Chris@10:  * Copyright (c) 2003, 2007-11 Matteo Frigo
Chris@10:  * Copyright (c) 2003, 2007-11 Massachusetts Institute of Technology
Chris@10:  *
Chris@10:  * This program is free software; you can redistribute it and/or modify
Chris@10:  * it under the terms of the GNU General Public License as published by
Chris@10:  * the Free Software Foundation; either version 2 of the License, or
Chris@10:  * (at your option) any later version.
Chris@10:  *
Chris@10:  * This program is distributed in the hope that it will be useful,
Chris@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
Chris@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Chris@10:  * GNU General Public License for more details.
Chris@10:  *
Chris@10:  * You should have received a copy of the GNU General Public License
Chris@10:  * along with this program; if not, write to the Free Software
Chris@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
Chris@10:  *
Chris@10:  */
Chris@10: 
Chris@10: #include "ifftw.h"
Chris@10: 
Chris@10: 
Chris@10: /* Given a solver which_dim, a vector sz, and whether or not the
Chris@10:    transform is out-of-place, return the actual dimension index that
Chris@10:    it corresponds to.  The basic idea here is that we return the
Chris@10:    which_dim'th valid dimension, starting from the end if
Chris@10:    which_dim < 0. */
Chris@10: static int really_pickdim(int which_dim, const tensor *sz, int oop, int *dp)
Chris@10: {
Chris@10:      int i;
Chris@10:      int count_ok = 0;
Chris@10:      if (which_dim > 0) {
Chris@10:           for (i = 0; i < sz->rnk; ++i) {
Chris@10:                if (oop || sz->dims[i].is == sz->dims[i].os)
Chris@10:                     if (++count_ok == which_dim) {
Chris@10:                          *dp = i;
Chris@10:                          return 1;
Chris@10:                     }
Chris@10:           }
Chris@10:      }
Chris@10:      else if (which_dim < 0) {
Chris@10:           for (i = sz->rnk - 1; i >= 0; --i) {
Chris@10:                if (oop || sz->dims[i].is == sz->dims[i].os)
Chris@10:                     if (++count_ok == -which_dim) {
Chris@10:                          *dp = i;
Chris@10:                          return 1;
Chris@10:                     }
Chris@10:           }
Chris@10:      }
Chris@10:      else { /* zero: pick the middle, if valid */
Chris@10: 	  i = (sz->rnk - 1) / 2;
Chris@10: 	  if (i >= 0 && (oop || sz->dims[i].is == sz->dims[i].os)) {
Chris@10: 	       *dp = i;
Chris@10: 	       return 1;
Chris@10: 	  }
Chris@10:      }
Chris@10:      return 0;
Chris@10: }
Chris@10: 
Chris@10: /* Like really_pickdim, but only returns 1 if no previous "buddy"
Chris@10:    which_dim in the buddies list would give the same dim. */
Chris@10: int X(pickdim)(int which_dim, const int *buddies, int nbuddies,
Chris@10: 	       const tensor *sz, int oop, int *dp)
Chris@10: {
Chris@10:      int i, d1;
Chris@10: 
Chris@10:      if (!really_pickdim(which_dim, sz, oop, dp))
Chris@10:           return 0;
Chris@10: 
Chris@10:      /* check whether some buddy solver would produce the same dim.
Chris@10:         If so, consider this solver unapplicable and let the buddy
Chris@10:         take care of it.  The smallest-indexed buddy is applicable. */
Chris@10:      for (i = 0; i < nbuddies; ++i) {
Chris@10:           if (buddies[i] == which_dim)
Chris@10:                break;  /* found self */
Chris@10:           if (really_pickdim(buddies[i], sz, oop, &d1) && *dp == d1)
Chris@10:                return 0; /* found equivalent buddy */
Chris@10:      }
Chris@10:      return 1;
Chris@10: }